DE102008008968A1 - Paper mold i.e. press mold, for manufacturing glass and plastic parts, has layer made of rough porous or foamed sintered ceramic material whose porosity is larger than porosity of fine pored layer - Google Patents

Abstract

The paper mold has a layer (10) coming in contact with a material to be poured and made of fine pored, sintered ceramic material. The material has a porosity of 10x 10 power -1 meter to 30 micrometer, a porosity portion between 5 and 60 percent, and layer thickness greater than 2 millimeter. Another layer (11) arranged behind the layer (10) is made of a rough porous or foamed sintered ceramic material whose porosity is larger than the porosity of the fine pored layer (10). A temperature stable and heat conducting fabric (15) is introduced between the layers.

Description

Technical area

The The invention relates to a working mold for producing ceramic Hollow or core cast components such as cans, figures, Sanitary ceramics, building ceramics, etc.

State of the art

cans, Figures, sanitary ware, building ceramics and the like Components have been in slip casting for centuries produced. This method is characterized in that pour the liquid slurry into a divisible plaster cavity mold and after the potting time the remaining slip from the Plaster mold removed. To shorten the shard formation time, is being introduced through channels recently Vacuum, often referred to as vacuum, in the plaster mold applied and the slip in the mold from above with compressed air applied.

Though thus the body formation time and also the drying time become shortened the plaster mold, but the main problem of the plaster molds, namely the non-existing abrasion resistance a long period, remains.

Become used porous plastic molds, although the service life significantly extended the working form, but it may be that the porosity is not the same everywhere and mold making becomes significantly more complex, as the porous Plastic also has a fading.

From the EP 607 402 is a method disclosed, are produced with the roof tiles and also Schlickergussteile. The fine-pored material of the layer coming into contact with the material to be pressed is sintered with the underlying layer of coarsely porous material or foam. The porous inner layer has a layer thickness between 0.1 to 2 mm.

From the DE 40 12 044 It is known to produce a core of a finely divided mass consisting of high-quality molding plaster, of an absorbent adjusted calcium silicate hydrate body, of an absorbent plastic body or of a porous ceramic or metallic body. This absorbent core is embedded in a protective layer of mold plaster, calcium silicate hydrate, a resin-cured inorganic binder, or an absorbent resin.

For the better removal of the water from the core becomes the outer one Protective layer additionally with water-permeable pores or channels.

plaster molds for slip casting of ceramic products must be dried after one or more impressions become. The water and the hard particles in the slip grip the plaster and decomposed it. Another reason for The renewal of plaster molds is that the contours blur and faces, ornaments u. not anymore be reproduced in detail.

Presentation of the invention

The object of the invention is therefore to provide a working form ( 1 and 2 ) to produce ceramic components in the slip casting process, which is shrinkage-free and porous and has a very high wear resistance and durability.

In the mold according to the invention, the layer coming into contact with the material to be slipped ( 10 ) of fine-pored and sintered ceramic, which has a thickness of> 2 mm.

There the ceramic working mold according to the invention both after drying and after firing without shrinkage, can they are poured onto a silicone mold. The significantly cheaper However, production process is the inventive Ceramic directly on the plastic mold, with the usual the plaster molds are made to pour and onto it to harden.

Behind the layer of fine-pored ceramic material ( 10 ) is in the preferred embodiment of the working form a foam ( 11 ), which is impregnated with ceramic material. After drying, this ceramic foam can be fired and there are ceramic webs and structures, on the one hand support the fine-pored ceramic layer and on the other hand produce open channels. Alternatively, instead of the ceramic foam and ceramic bonded mineral spheres z. B. be used from lightweight materials. As a result, a vacuum can be applied to the fine-pore ceramic and the water is sucked through the fine-pored ceramic layer into the underlying structure and is discharged to the outside.

Behind this layer ( 11 ), another layer ( 12 ) are cast from a ceramic material, with which the ceramic foam or the ceramic bonded mineral balls are covered, so that a vacuum is possible.

Become now all 3 layers burned together they sinter to one Unit.

After firing the layers ( 10 ) ( 11 ) and ( 12 ) can be behind the layer of ceramic Material ( 12 ) a layer of plastic o. Ä. Material ( 13 ) are poured so that a vacuum is possible or it is the cover layer ( 12 ) made of ceramic material vacuum-tight. It is also possible to use the layer ( 12 ), but the covering layer ( 13 ) directly onto the ceramic foam ( 12 ) to pour.

In a less preferred embodiment of the working mold, foam or a similar organic material ( 11 ), without being impregnated with a ceramic material, behind the layer of fine-pored ceramic material ( 10 ) are formed. Behind this layer of foam can be poured again a layer of a ceramic material, with which the foam is covered.

If now all 3 layers are fired, the foam burns ( 11 ) and it creates a cavity with which a vacuum is possible, through which the water can be sucked out of the fine-pored layer and can be discharged to the outside.

After firing the layers ( 10 ) ( 11 ) and 12 can be behind the layer of ceramic material ( 12 ) a layer of plastic o. Ä. Material ( 13 ) are poured so that a vacuum is possible or it is the cover layer ( 12 ) made of ceramic material vacuum-tight.

In 2 is a method shown in an alternative method Schlickergussformen be prepared from a ceramic.

In the mold according to the invention, the layer coming into contact with the material to be slipped ( 20 ) again of fine-pored and sintered ceramic, which has a thickness of> 2 mm.

Behind the layer of fine-pored ceramic material ( 20 ), a second layer ( 21 ), consisting of fine-pored or coarse-pored ceramic material. In this layer ( 21 ) channels ( 22 ) are introduced, which can be acted upon by connections with negative pressure or compressed air.

Thereby a vacuum can be applied to the fine-pore ceramic and the Water is lost through the fine and coarse-pored ceramic layer derived outside.

After firing the layers ( 20 ) and ( 21 ) behind the layer of ceramic material ( 20 ) or ( 21 ) a layer of plastic o. Ä. Material ( 23 ) are poured so that a vacuum is possible. If the mold should not be operated with vacuum then the cover layer ( 23 ) and drying in the known form is thus possible.

Slip molds are usually made in several parts, so that the components can be removed from the mold. It is important that the contact surfaces ( 14 ) of the multi-part molds are performed plane-parallel to each other, so that the slip enters only into the cavities. This is not always possible in parallel with ceramic forms. It is therefore proposed to create a cavity in the production of the fine-pored ceramic layer at the contact surfaces of the multi-part molds. After firing of the multilayered working mold, this cavity can be removed in a separate operation ( 14 ) are poured with resin or similar materials so that these contact surfaces are parallel to each other in multi-part working forms.

It is further proposed that in a layer or between any two layers of the mold a temperature-stable and heat-conducting fabric ( 15 ), z. As metal fabric, insert and sinter this with. If this fabric is heated during operation, the slurry can be heated from the inside and thus dried faster.

One Cover (not shown) with a compressed air connection can the Completing slip of the air pressure and allows thus the admission of the slip with compressed air.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - EP 607402 [0005]
• - DE 4012044 [0006]

Claims (19)

Working mold for casting ceramic articles in hollow or core casting characterized in that a coming into contact with the material to be cast in contact ( 10 ) of the 1 respectively. ( 20 ) of the 2 consists of fine-pored, sintered ceramic material having a porosity of 10 Á (10 × 10 ^-10 m) to 30 microns, a porosity depending on the material to be cast between 5% and 60% and a layer thickness> 2 mm and that the behind layer ( 11 of the 1 ) respectively. ( 21 of the 2 ) consists of a coarse-pored or foamed sintered ceramic material whose porosity is greater than the porosity of the fine-pored layer ( 10 ) of the 1 respectively. ( 20 ) of the 2 , Mold according to claim 1, characterized in that the fine-pored sintered ceramic material of the layer ( 10 ) of the 1 respectively. ( 20 ) of the 2 consists of corundum, mullite, zirconium dioxide, silicon carbide or silicon nitride or mixtures thereof. Mold according to claim 2, characterized in that the layer ( 11 ) of the 1 respectively. ( 21 ) of the 2 made of foamed or coarsely porous ceramic material of corundum, mullite, zirconium dioxide, silicon carbide or silicon nitride or of mixtures thereof or of bound or loose mineral spheres. Mold according to claim 3, characterized in that, if necessary, behind the layer ( 11 ) a non-foamed layer ( 12 ), preferably made of ceramic, is applied. Mold according to claim 4, characterized in that the layer ( 11 ) can be partially eliminated and thereby creates a cavity or multiple cavities arise. Mold according to claim 4, characterized in that the layer ( 11 ) can be omitted and no cavity is formed when the layer ( 12 ) directly on the layer ( 10 ) is applied. Mold according to claims 5 or 6, characterized in that the layers ( 10 ) 11 ) and ( 12 ) are sintered individually or together. Mold according to claim 7, characterized in that between the layers ( 10 ) and ( 11 ) or within the layers, if necessary, a temperature-stable and heat-conducting tissue ( 15 ) is introduced. Mold according to Claim 8, characterized in that, if required, the mold is provided with a vacuum-tight material ( 13 and or 14 ) is sheathed. The working surface of the layer ( 10 ) is to be released. Mold according to claim 9, characterized in that They use vacuum or pressure in the working mold and with pressure in the Sludge mass can be applied. Mold according to claim 2, characterized in that the layers ( 20 ) and ( 21 ) are sintered individually or together. Mold according to claim 2, characterized in that the layer ( 21 ) and the entire component of the material of the layer ( 20 ) consists. Mold according to claims 11 and 12, characterized in that between the layers ( 20 ) and ( 21 ) or within the layers, if necessary, a temperature-stable and heat-conducting tissue ( 15 ) is introduced. Mold according to claim 13, characterized in that the mold is cast with channels ( 22 ), which are located just below the molding area, is provided. Mold according to claim 14, characterized in that the channels ( 22 ) can be applied with vacuum or pressure. Mold according to claim 15, characterized in that, if required, the mold is provided with a vacuum-tight material ( 23 and or 14 ) is sheathed. The working surface of the layer ( 20 ) is to be released. Mold according to claim 16, characterized in that They use vacuum or pressure in the working mold and with pressure in the Sludge mass can be applied. Mold according to claims 10 and 17 characterized characterized in that each part of the mold with a vacuum or Pressure port is provided. Use of the mold according to claims 1 up to 18 also as a mold, during metal casting, during production of glasses or plastic parts with or without vacuum.